<?php

namespace App\Services\Pos;

use App\Models\PosSale;
use App\Models\PosSaleLine;
use App\Models\User;
use App\Services\Pay\PayClient;
use Illuminate\Support\Str;
use RuntimeException;

class PosSaleService
{
    public function __construct(
        private PayClient $pay,
        private PosTimelineService $timeline,
    ) {}

    /**
     * @param  list<array{product_id?: ?int, name: string, unit_price_minor: int, quantity: int}>  $lines
     * @param  array{customer_name?: ?string, customer_email?: ?string, customer_phone?: ?string, crm_customer_id?: ?int, location_id?: ?int, currency?: string}  $meta
     */
    public function createSale(User $merchant, array $lines, array $meta = []): PosSale
    {
        $normalized = $this->normalizeLines($lines);
        if ($normalized === []) {
            throw new RuntimeException('Add at least one item to the sale.');
        }

        $subtotal = collect($normalized)->sum('line_total_minor');
        if ($subtotal <= 0) {
            throw new RuntimeException('Sale total must be greater than zero.');
        }

        $currency = strtoupper((string) ($meta['currency'] ?? config('pos.default_currency', 'GHS')));

        $sale = PosSale::create([
            'owner_ref' => $merchant->public_id,
            'location_id' => $meta['location_id'] ?? null,
            'reference' => 'POS-'.strtoupper(Str::random(12)),
            'status' => PosSale::STATUS_PENDING,
            'payment_method' => PosSale::METHOD_PAY,
            'customer_name' => $meta['customer_name'] ?? null,
            'customer_email' => $meta['customer_email'] ?? null,
            'customer_phone' => $meta['customer_phone'] ?? null,
            'crm_customer_id' => $meta['crm_customer_id'] ?? null,
            'subtotal_minor' => $subtotal,
            'total_minor' => $subtotal,
            'currency' => $currency,
        ]);

        foreach ($normalized as $index => $line) {
            PosSaleLine::create([
                'pos_sale_id' => $sale->id,
                'product_id' => $line['product_id'] ?? null,
                'name' => $line['name'],
                'unit_price_minor' => $line['unit_price_minor'],
                'quantity' => $line['quantity'],
                'line_total_minor' => $line['line_total_minor'],
                'position' => $index,
            ]);
        }

        return $sale->fresh('lines');
    }

    /**
     * @return array{sale: PosSale, checkout_url: string}
     */
    public function initiatePayCheckout(PosSale $sale, User $merchant): array
    {
        if ($sale->isPaid()) {
            throw new RuntimeException('This sale is already paid.');
        }

        $sale->load('lines');
        $callbackUrl = route('pos.sales.callback', $sale);

        $payOrder = $this->pay->createCheckout([
            'merchant' => $merchant->public_id,
            'fee_tier' => 'sales',
            'source_service' => 'pos',
            'source_ref' => (string) $sale->id,
            'callback_url' => $callbackUrl,
            'customer_name' => $sale->customer_name,
            'customer_email' => $sale->customer_email,
            'customer_phone' => $sale->customer_phone,
            'line_items' => $sale->lines->map(fn (PosSaleLine $line) => [
                'name' => $line->name,
                'unit_price_minor' => $line->unit_price_minor,
                'quantity' => $line->quantity,
            ])->all(),
            'metadata' => [
                'pos_sale_id' => $sale->id,
                'pos_reference' => $sale->reference,
            ],
        ]);

        $checkoutUrl = (string) ($payOrder['checkout_url'] ?? '');
        if ($checkoutUrl === '') {
            throw new RuntimeException('Could not start checkout. Please try again.');
        }

        $sale->forceFill([
            'payment_method' => PosSale::METHOD_PAY,
            'pay_order_id' => $payOrder['id'] ?? null,
            'payment_reference' => $payOrder['reference'] ?? null,
        ])->save();

        return [
            'sale' => $sale->fresh('lines'),
            'checkout_url' => $checkoutUrl,
        ];
    }

    public function recordCashPayment(PosSale $sale): PosSale
    {
        if ($sale->isPaid()) {
            throw new RuntimeException('This sale is already paid.');
        }

        $sale->forceFill([
            'payment_method' => PosSale::METHOD_CASH,
            'status' => PosSale::STATUS_PAID,
            'paid_at' => now(),
        ])->save();

        $sale = $sale->fresh('lines');
        $this->timeline->pushPaidSale($sale);

        return $sale;
    }

    public function completePayCheckout(string $paymentReference): PosSale
    {
        $sale = PosSale::query()
            ->where('payment_reference', $paymentReference)
            ->where('status', PosSale::STATUS_PENDING)
            ->firstOrFail();

        $payOrder = $this->pay->verify($paymentReference);

        $sale->forceFill([
            'status' => PosSale::STATUS_PAID,
            'total_minor' => (int) ($payOrder['amount_minor'] ?? $sale->total_minor),
            'pay_order_id' => $payOrder['id'] ?? $sale->pay_order_id,
            'paid_at' => now(),
        ])->save();

        $sale = $sale->fresh('lines');
        $this->timeline->pushPaidSale($sale);

        return $sale;
    }

    /**
     * @param  list<array{product_id?: ?int, name: string, unit_price_minor: int, quantity: int}>  $lines
     * @return list<array{product_id?: ?int, name: string, unit_price_minor: int, quantity: int, line_total_minor: int}>
     */
    private function normalizeLines(array $lines): array
    {
        $out = [];

        foreach ($lines as $line) {
            $qty = max(1, (int) ($line['quantity'] ?? 1));
            $unit = max(0, (int) ($line['unit_price_minor'] ?? 0));
            $name = trim((string) ($line['name'] ?? ''));

            if ($name === '' || $unit <= 0) {
                continue;
            }

            $out[] = [
                'product_id' => $line['product_id'] ?? null,
                'name' => $name,
                'unit_price_minor' => $unit,
                'quantity' => $qty,
                'line_total_minor' => $unit * $qty,
            ];
        }

        return $out;
    }
}